|Jmol 3D model||Interactive image|
|Molar mass||89.093 g/mol|
|Appearance||white bipyramidal crystals|
|Density||1.437 g/cm3 (19 °C)|
|Melting point||207 °C (405 °F; 480 K) (decomposes)|
|54.5 g/100 mL|
|Solubility||soluble in methanol. Insoluble in diethyl ether, acetone|
|Safety data sheet|||
|Lethal dose or concentration (LD, LC):|
LD50 (median dose)
|1000 mg/kg (rat, oral)|
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
|what is ?)(|
β-Alanine (or beta-alanine) is a naturally occurring beta amino acid, which is an amino acid in which the amino group is at the β-position from the carboxylate group (i.e., two atoms away, see Figure 1). The IUPAC name for β-alanine is 3-aminopropanoic acid. Unlike its counterpart α-alanine, β-alanine has no stereocenter.
β-Alanine is not used in the biosynthesis of any major proteins or enzymes. It is formed in vivo by the degradation of dihydrouracil and carnosine. It is a component of the naturally occurring peptides carnosine and anserine and also of pantothenic acid (vitamin B5), which itself is a component of coenzyme A. Under normal conditions, β-alanine is metabolized into acetic acid.
β-Alanine is the rate-limiting precursor of carnosine, which is to say carnosine levels are limited by the amount of available β-alanine, not histidine. Supplementation with β-alanine has been shown to increase the concentration of carnosine in muscles, decrease fatigue in athletes and increase total muscular work done. Simply supplementing with carnosine is not as effective as supplementing with β-alanine alone since carnosine, when taken orally, is broken down during digestion to its components, histidine and β-alanine. Hence, by weight, only about 40% of the dose is available as β-alanine.
L-Histidine, with a pKa of 6.1 is a relatively weak buffer over the physiological intramuscular pH range. However, when bound to other amino acids, this increases nearer to 6.8-7.0. In particular, when bound to β-alanine, the pKa value is 6.83, making this a very efficient intramuscular buffer. Furthermore, because of the position of the beta amino group, β-alanine dipeptides are not incorporated into proteins, and thus can be stored at relatively high concentrations (millimolar). Occurring at 17–25 mmol/kg (dry muscle), carnosine (β-alanyl-L-histidine) is an important intramuscular buffer, constituting 10-20% of the total buffering capacity in type I and II muscle fibres.
Even though much weaker than glycine (and, thus, with a debated role as a physiological transmitter), β-alanine is an agonist next in activity to the cognate ligand glycine itself, for strychnine-sensitive inhibitory glycine receptors (GlyRs) (the agonist order: glycine ≫ β-alanine > taurine ≫ alanine, L-serine > proline).
Athletic performance enhancement
- The Merck Index: An Encyclopedia of Chemicals, Drugs, and Biologicals (11th ed.), Merck, 1989, ISBN 091191028X, 196.
- Weast, Robert C., ed. (1981). CRC Handbook of Chemistry and Physics (62nd ed.). Boca Raton, FL: CRC Press. p. C-83. ISBN 0-8493-0462-8..
- Derave W, Ozdemir MS, Harris R, Pottier A, Reyngoudt H, Koppo K, Wise JA, Achten E (August 9, 2007). "Beta-alanine supplementation augments muscle carnosine content and attenuates fatigue during repeated isokinetic contraction bouts in trained sprinters". J Appl Physiol 103 (5): 1736–43. doi:10.1152/japplphysiol.00397.2007. PMID 17690198.
- Hill CA, Harris RC, Kim HJ, Harris BD, Sale C, Boobis LH, Kim CK, Wise JA (2007). "Influence of beta-alanine supplementation on skeletal muscle carnosine concentrations and high intensity cycling capacity". Amino Acids 32 (2): 225–33. doi:10.1007/s00726-006-0364-4. PMID 16868650.
- Bate-Smith, EC (1938). "The buffering of muscle in rigor: protein, phosphate and carnosine". Journal of Physiology 92 (3): 336–343. PMC 1395289. PMID 16994977.
- Mannion, AF; Jakeman, PM; Dunnett, M; Harris, RC; Willan, PLT (1992). "Carnosine and anserine concentrations in the quadriceps femoris muscle of healthy humans". Eur. J. Appl. Physiol 64: 47–50. doi:10.1007/BF00376439.
- Encyclopedia of Life Sciences Amino Acid Neurotransmitters. Jeremy M Henley, 2001 John Wiley & Sons, Ltd. doi:10.1038/npg.els.0000010, Article Online Posting Date: April 19, 2001
- Trexler, Eric T.; Smith-Ryan, Abbie E.; Stout, Jeffrey R.; Hoffman, Jay R.; Wilborn, Colin D.; Sale, Craig; Kreider, Richard B.; Jäger, Ralf; Earnest, Conrad P.; Bannock, Laurent; Campbell, Bill; Kalman, Douglas; Ziegenfuss, Tim N.; Antonio, Jose (2015). "International society of sports nutrition position stand: Beta-Alanine". Journal of the International Society of Sports Nutrition 12 (1). doi:10.1186/s12970-015-0090-y. ISSN 1550-2783.
- Beck, Kathryn; Thomson, Jasmine S; Swift, Richard J; von Hurst, Pamela R (2015). "Role of nutrition in performance enhancement and postexercise recovery". Open Access Journal of Sports Medicine: 259. doi:10.2147/OAJSM.S33605. ISSN 1179-1543.
- Aspartic acid-beta-4-nitroanilide in the ChemIDplus database